[Federal Register Volume 69, Number 1 (Friday, January 2, 2004)]
[Notices]
[Pages 120-121]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-32252]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-335]


Florida Power and Light Company, St. Lucie Plant, Unit No. 1; 
Exemption

1.0 Background

    The Florida Power and Light Company (FPL, the licensee) is the 
holder of Facility Operating License No. DPR-67, which authorizes 
operation of the St. Lucie Plant, Unit No. 1. The license provides, 
among other things, that the facility is subject to all rules, 
regulations, and orders of the U.S. Nuclear Regulatory Commission (NRC, 
the Commission) now or hereafter in effect.
    The facility consists of a pressurized water reactor located in St. 
Lucie County, Florida.

2.0 Request/Action

    Title 10 of the Code of Federal Regulations (10 CFR), part 50, 
appendix R, Section III.G.2.d specifies separation of cables and 
equipment and associated nonsafety circuits of redundant trains by a 
horizontal distance of more than 20 feet with no intervening 
combustibles or fire hazards as one means of providing adequate fire 
protection for redundant trains of safe-shutdown equipment located 
inside noninerted containments.
    On February 21, 1985, the NRC approved an exemption from Appendix R 
to allow redundant trains in the St. Lucie Unit 1 containment to have 
less than 20 feet horizontal separation. On March 5, 1987, the NRC 
approved a revision to this exemption to allow minimal intermittent 
combustibles between the redundant trains. The staff approved the 
exemptions based, in part, on the redundant trains being separated by 
more than 7 feet horizontally and 25 feet vertically. The licensee 
subsequently determined that the assumption of 25 feet vertical 
separation was incorrect. The proposed action resubmits the exemption 
request and provides a detailed fire model to demonstrate that, with 
the existing vertical separation and a minimum of 7 feet horizontal 
separation, a fire in one train will not damage the redundant train. 
The revised request limits the exemption to the cable trays in the 
containment annular region between radial column lines 2 and 6 with the 
following assumptions:

    (1) Redundant trays are at least 7 feet apart with no intervening 
combustibles
    (2) Electrical cabinets near the redundant trains are enclosed with 
no ventilation openings
    (3) Cables crossing redundant trays are in conduit and protected
    (4) The bottom tray in each stack of cable trays is fully enclosed 
by a noncombustible cover
    (5) Vertical cable trays have noncombustible covers
    (6) Existing cables are covered with fire retardant coating
    (7) New cables added will be IEEE 383 qualified and limited in 
number by the fire analysis.
    In summary, the exemption would be revised to allow separation of 
cables of redundant trains by a horizontal distance of at least 7 feet 
with no intervening combustibles inside containment in the annular 
region between radial column lines 2 and 6.

3.0 Discussion

    Pursuant to 10 CFR 50.12, the Commission may, upon application by 
any interested person or upon its own initiative, grant exemptions from 
the requirements of 10 CFR part 50, when (1) the exemptions are 
authorized by law, will not present an undue risk to public health or 
safety, and are consistent with the common defense and security, and 
(2) special circumstances are present. These include the special 
circumstance that application of the regulation is not necessary to 
achieve the underlying purpose of the rule. The underlying purpose of 
the rule is to limit fire damage so that one train of systems necessary 
to achieve and maintain hot shutdown conditions remains free of fire 
damage.
    The staff examined the licensee's rationale to support the revised 
exemption request and concluded that granting the exemption to allow 
less than 20 feet horizontal separation between redundant cable trays 
would meet the underlying purpose of 10 CFR part 50. The licensee 
provided a detailed fire model that postulates a self-initiated cable 
fire, spreading horizontally and vertically in one stack of cable trays 
until the original combustible material (i.e., cable jacket insulation) 
is completely consumed. Based on the maximum postulated fire, a maximum 
radiant heat flux and the heat flux imposed on the redundant cable 
trays can be calculated to see if ignition of the redundant cables is 
possible. The model demonstrates that the resulting heat flux from the 
largest postulated exposure fire is less than half the heat flux needed 
to ignite the redundant cable trays. There was a degree of conservatism 
throughout the correlations and, therefore, a larger safety factor 
probably exists.
    Based upon a consideration of the licensee's fire model, which 
indicates that, with a minimum of 7 feet horizontal separation, a cable 
fire in one train is highly unlikely to damage cables in the redundant 
train, the staff concludes that application of the regulation is not 
necessary to achieve the underlying purpose of the rule.
    Therefore, the staff concludes that pursuant to 10 CFR 
50.12(a)(2)(ii) special circumstances are present and that an exemption 
may be granted to allow less than 20 feet horizontal separation between 
redundant trains.

4.0 Conclusion

    Accordingly, the Commission has determined that, pursuant to 10 CFR 
50.12(a), the exemption is authorized by law, will not present an undue 
risk to the public health and safety, and is consistent with the common 
defense and security. Also, special circumstances are present. 
Therefore, the Commission hereby grants FPL an exemption from the 
requirements of 10 CFR part 50, appendix G, Section II.G.2.d for St. 
Lucie Unit No. 1.
    Pursuant to 10 CFR 51.32, the Commission has determined that the 
granting of this exemption will not have a significant effect on the 
quality of the human environment (68 FR 69728).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 24th day of December 2003.

[[Page 121]]

    For the Nuclear Regulatory Commission.
Ledyard B. Marsh,
Director, Division of Licensing Project Management, Office of Nuclear 
Reactor Regulation.
[FR Doc. 03-32252 Filed 12-31-03; 8:45 am]
BILLING CODE 7590-01-P